Barus effect in polymer flows through cylindrical and flat dies

The determination of the swell factor of a polymer jet extruded from a cylindrical or flat die is examined. Relations are obtained for the dependence of the swell factor on shear rate and shear stress, expressed in terms of the constants of the rheological model.Scientific Research Institute of Plastics, Moscow. Kiev Polytechnic Institute. Translated from Mekhanika Polimerov, No. 3, pp. 487–492, May–June, 1976.     

Non-newtonian viscosity of certain precopolymers of n-butyl methacrylate

The viscous flow of precopolymers of n-butyl methacrylate and triethylene glycol dimethacrylate at various shear rates is considered. The dynamic viscosity of the precopolymers is shown to depend on the conversion ratio.Kiev Branch, All-Union Scientific-Research Institute of Complex Problems of Polygraphy in Special Types of Printing. Institute of Chemistry of High-Molecular-Weight Compounds, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1096–1097, November–December, 1971.     

Effect of the properties of the material of the buckling of a plate

In [2] it was shown with reference to the cylindrical bending of a plate that the Kirchhoff-Love hypothesis is asympototically accurate for determining the critical load irrespective of the properties of the material. However, the question of the dependence of the critical load on the material properties was left unexplored. This question is now numerically investigated. Curves characterizing the variation of the critical load with relative shear modulus are presented.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 355–357. March–April, 1969.     

Stability of composite shells with an elastic core

The stability in axial compression of orthotropic cylindrical shells with an elastic core is investigated with allowance for the following factors: transverse shear strains in the shell material, precritical state of stress of the core, and the moments due to the surface forces exerted on the shell by the core. The numerical results obtained are compared with the results of approximate methods in which the above-mentioned factors are disregarded.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 544–547, May–June, 1976.     

Effect of proton-electron irradiation on the strength of a glass-reinforced plastic and its components

The action of protons and electrons on the properties of glass strands under vacuum conditions has been experimentally investigated. The experimental procedure is described. The effects of irradiation, strain rate, and reduced temperature and pressure on the properties of glass reinforcement and glass-reinforced plastics are estimated.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev; Physicotechnical Institute of Low Temperatures, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 755–760, July–August, 1970.     

Concerning the investigation of the supermolecular structure of polymers with a three-dimensional network

The results of an investigation of the structure and properties of a series of crosslinked polymers are presented. It is shown that the structure is determined by the chemical structure of the starting components and the method of synthesis.Institute of Chemistry of High-Molecular Compounds, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 5, pp. 934–936, September–October, 1970.     

Flow of polymer melts in a combined extruder

A viscoelastic incompressible fluid, modeled by the White-Metzner equation, flows in a combined extruder. Approximate expressions are obtained for the secondary flows in the disk zone of the machine whose presence has been confirmed experimentally. By means of these expressions it is possible to determine the total shear deformation of an element of the melt as it passes through the extruder.Kiev Polytechnic Institute. L'vov Polytechnic Institute. Translated from Mekhanika Polimerov, No. 2, pp. 351–358, March–April, 1972.     

Analogies and the modeling of composites

On the basis of the solution of a series of problems of the distribution of static and dynamic fields of various physical kinds in the microstructure of composite materials reinforced with dispersed particles or fibers analogies are established between the stress, displacement, temperature, electromagnetic, and other fields subject to certain similarity criteria imposed on the properties of the components.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1028–1037, November–December, 1969.     

Quasilinearization method for coupled dynamic problems of thermoviscoelasticity

Use of the quasilinearization method is proposed for the solution of coupled dynamic (particularly, quasistatic) problems of thermoviscoelasticity under cyclic loading. The coupled problems under consideration here include vibrations of a one-dimensional body (beam, plate, shell) and shear vibrations of a hollow cylinder made of a material with temperature-dependent properties, with the principle of temperature-time analogy applicable in the latter case. The quasilinearization method is shown to be a fast converging one when applied to the solution of these problems.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 2, pp. 310–316, March–April, 1976.     

On the applicability of two-dimensional applied theories to problems of the stability of axially loaded cylindrical shells made of materials with low shear stiffness

The applicability of two-dimensional applied theories of the Kirchhoff-Love, Timoshenko, and Ambartsumyan types to problems of the stability of shells with low shear stiffness [1] is discussed. The critical loads given by these theories are compared with those recently obtained [6–8] by solving the problem of the stability of a cylindrical shell on the basis of general solutions [3, 4] of the three-dimensional linearized equations of the theory of elasticity [5].Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. L'vov Polytechnic Institute. Translated from Mekhanika Polimerov, No. 1, pp. 141–143, January–February, 1970.     

State of stress of flexible viscoelastic plates with an opening

The problem of the state of stress of flexible plates with an opening is investigated with allowance for the viscoelastic properties of the material. The basic equations and the corresponding boundary conditions are formulated. The boundary value problem is solved by numerical integration. The effect of the creep properties of the material on the stress redistribution in the plate is investigated with reference to polymethyl methacrylate. It is shown that the angle of rotation, the ring moment, and the ring forces at the edge of the opening vary with time and as a function of the load.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 708–713, July–August, 1971.     

Stability of a transversely isotropic cylindrical shell in axial compression

The problem of the stability of a transversely isotropic cylindrical shell subjected to axial compression is considered with the aid of three-dimensional linearized equations for small subcritical strains. Transcendental equations are obtained for the critical loads corresponding to axisymmetric and nonaxisymmetric deformation. It is shown that in the case of the axisymmetric buckling mode the Kirchhoff-Love hypothesis is asymptotically exact irrespective of the properties of the material. The dependence of the critical load on the properties of the shell material is investigated numerically. Graphs of the variation of the critical load with relative shear modulus are presented.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1064–1068, November–December, 1969.     

Temperature dependence of the thermophysical properties of a Teflon — Bronze antifriction material

The effect of temperature and the concentration of the dispersed metallic filler on the thermophysical properties of a Teflon-based composition have been experimentally investigated. The results of the measurements of the thermophysical characteristics of the filled and unfilled Teflon are evaluated with allowance for the thermal conductivity of the components, their physicochemical interaction, and the change in the structure of the heterogeneous systems investigated.Deceased.A. M. Gor'kii Kiev State Pedagogical Institute; Institute of Colloidal Chemistry and the Chemistry of Water, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1053–1056, November–December, 1971.     

Non-Gaussian analysis and hypergroups

NANU Mathematical Institute, Kiev, Ukraine and MCS University, Lublin, Poland; NANU Mathematical Institute, Kiev, Ukraine and Bielefeld University, Germany. Translated from Funktsional'nyi Analiz i Ego Prilozheniya, Vol. 29, No. 3, pp. 51–55, July–September, 1995.     

Stability of the momentum state of a three-layer orthotropic cylindrical casing at uniform and nonuniform external pressures

The effect of the momentum subcritical state on the stability of three-layer orthotropic cylindrical casings at external pressures was investigated. The problem is solved by means of equations that take into account transversal shear. It is shown that in some cases the effect of the subcritical state momentum on the critical load parameter is significant.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 5, pp. 874–879, September–October, 1972.     

Solution of two-dimensional boundary-value problems of the theory of thin composite shells

Discrete analogues of the boundary-value problems of a two-dimensional refined theory of anisotropic shells taking into account the transverse shear deformation are presented. The systems of resolving equations in the general form are obtained for arbitrary nonshallow shells of variable curvature whose coordinate lines of the reduction surface may not coincide with the lines of principal curvatures. The algebraic problems of determining the stress-strain state in shells made of composite materials with stress concentrators under various kinds of loads are obtained as particular cases of the schemes presented. The results of calculating the stress concentration near a nonsmall circular hole in a transversely isotropic nonshallow spherical shell under internal pressure are presented. The dependences of stress concentration factors on the hole dimension and on a change in the shear stiffness of the shells are studied. A comparison between the calculation results obtained within the framework of the theories of shallow and nonshallow shells is given.Presented at the 11th International Conference on the Mechanics of Composite Materials (Riga, June 11–15, 2000).Timoshenko Institute of Mechanics, Ukranian National Academy of Sciences, Kiev, Ukraine. Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 4, pp. 465–472, July–August, 2000.     

Probability characteristics of the shear modulus of glass-reinforced plastics

The results of tests on wound glass-reinforced plastic specimens based on ÉFB-4 epoxy-phenolic-butyral composition and NS 55/6 glass strand reinforcement with a paraffin finish have been subjected to a statistical analysis with the object of determining the probability characteristics of the shear modulus. The shear modulus is determined for unidirectional structures and structures with reinforcement ratios of 1:1, 1:2, and 3:2. The results of the tests are used to determine the mathematical expectation, variance, and probability density function of the shear modulus.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 1, pp. 160–162, January–February, 1973.     

Dependence of the properties of polycaproamide obtained in the presence of benzhydrazide on the symmetry type of the unit cell

The structure and properties of polycaproamide obtained in the presence of benzhydrazide have been studied. They are shown to depend on the duration of application of pressure in the mold. Under tensile deformation a transition from hexagonal to monoclinic polycaproamide takes place in the neck.Lugansk Machine-Building Institute. Institute of the Chemistry of High-Molecular Compounds, As UkrSSR, Kiev. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1125–1127, November–December, 1968.     

Lamellar structure and plasticity micromechanisms in bulk crystalline polymers. Communication 1

It is shown by electron microscopy that the lamellar structure typical of bulk crystalline polymers is identical in its structural-morphological characteristics with the typical products of martensite transformations in metal systems. It is also established that the polymer crystallization process has the typical characteristics of transformations governed by the shear (martensite) mechanism. These conclusions are used as a basis for an examination of the principal factors controlling the formation of the real structure of bulk polymers. The thermodynamic conditions under which bulk polymers crystallize require that the lamellar-spherulitic structure be formed in accordance with a self-consistent shear mechanism. In accordance with the new model, the spherulites represent an organization of the martensite lamellae in which the structural stress fields are mutually compensated. The proposed model underlines the fact that polycrystalline polymers and metal systems in the martensitic state are structurally similar materials.E. O. Paton Electrowelding Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 387–394, May–June, 1976.     

Lamellar structure and plasticity micromechanisms in bulk crystalline polymers. Communication 2

Conclusions 1. It has been experimentally established that the deformation of crystalline polymers is accompanied by the shear transitions between lamellar crystals of different orientations characteristic of martensitic structures.2. It is concluded that the reversibility of the large deformations of linear polymers is martensitic in nature.For communication 1 see [1].E. O. Paton Electrowelding Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 963–969, November–December, 1976.